This invention relates to grid drain systems, and in particular to a pitless drainage system for removing water from at least a portion of a footing drain in which water is collected at a subterranean location.
Typical sump pump systems include an interior sump pit within the walls of a structure. U.S. Pat. Nos. 4,631,001 and 5,314,313 depict such systems. Footings of the building in which the sump system is located drain to the interior sump pit, and when water within the sump pit reaches a particular level, a sump pump is activated and water is pumped out of the structure. Such systems have been in use for decades.
Many problems exist with typical sump systems. Since the sump pit is located inside the structure, if the sump pump fails or becomes overwhelmed, the interior of the structure can become flooded. Also, because the sump pit is located inside the structure, a certain portion of the interior space of the structure must be reserved for the sump pit and related equipment. Furthermore, since pumping occurs from inside the building to outside the building, any valve failures can also result in flooding of the interior of the structure. Finally, because water is located exterior to the structure, current systems are inherently inefficiently designed, allowing water to enter the structure, and then requiring the water to be pumped outside again.
U.S. Pat. No. 4,298,294 discloses a system for lowering the water level about a structure by using an exterior wet well. While such a structure can be advantageous, particularly in very pervious soil systems, a disadvantage is that for larger structures, two or more of the systems of this patent might be required to provide proper dewatering. Also, the system requires a fairly large diameter bore, similar to the typical interior sump pit, but sunk to a considerable depth below the ground surface.
The invention overcomes the above deficiencies of the prior art and others, by providing a pitless drainage system for removing water from at least a portion of a footing drain in which water is collected at a subterranean location. The system includes a vertical riser extending from a top at an upper elevation above ground to a bottom at a lower elevation at the subterranean location. The riser is located proximate footing drains around the structure. A well collector is located in the vertical riser at the bottom, the well collector having ingresses allowing water to flow therethrough. A protective cap is secured at the top of the riser. A submersible pump extends down the riser into the well collector, and a water level control is provided, comprising an upper level pump activation and a lower level pump activation.
In accordance with the preferred form of the invention, the vertical riser comprises a pipe, which preferably is made of plastic or other impervious material. Metal can also be used, but is not as versatile, and, depending on the type of metal, could be subject to corrosion.
The well collector preferably comprises an extended portion of the pipe. It can be either an integral portion of the pipe, or a separate element secured to the pipe. The ingresses comprise elongated vertical slots in the well collector, the slots being sized so that exterior material, such as soil and gravel, cannot easily enter the well collector.
The cap comprises a cover which is attached to the top of the vertical riser. Preferably, the cover is removable for ready access to the submersible pump and upper and lower level pump activations.
The upper and lower pump activations comprise pressure sensor tubes. Preferably, an over level pump activation is included, as well. The over level pump activation also comprises a pressure sensor tube.
The pitless drainage system extends down to a subterranean location beneath the footing drain, so that water from the footing drain can readily be removed. Preferably, gravel or relatively large rock is installed in the vicinity of the well collector to promote free flow of water into the well collector.